The present invention relates to an automatic milling and drilling machine.
An automatic machining apparatus, for instance for milling and/or boring a workpiece, has as described in U.S. Pat. No. 5,781,983 of Gruner at least one work unit with a rotary tool for machining a workpiece held in a machining zone. The workpiece is secured to a workpiece holder that has a workpiece chuck. The chuck can be moved into a workpiece change station where it can be switched with another workpiece. To change workpieces, a workpiece is picked up and put down from above by the holding device. For machining the workpiece is held from above by the workpiece carrier.
Such an arrangement is relatively effective, but somewhat bulky. In addition the path of movement of the workpiece is somewhat complex.
It is therefore an object of the present invention to provide an improved automatic machining apparatus.
Another object is the provision of such an improved automatic machining apparatus which overcomes the above-given disadvantages, that is which is of simple construction, which has a particularly simple and rational system for displacing the workpieces, and which achieves a high production efficiency.
These objects are achieved according to the invention in a machining apparatus having a lower housing part, an upper housing part having a lower side, and a plurality of support posts fixed to the upper and lower parts and holding the upper part fixedly at a spacing above the lower part in monoblock fashion. A tool holder displaceable parallel to a horizontal tool axis on the lower side of the upper housing part carries a chuck rotatable about the tool axis and adapted to hold a machining tool. A supply station on the lower part offset horizontally perpendicular to the tool axis from the tool holder is adapted to hold a plurality of the workpieces. A cross slide connected between the upper housing part and a workpiece chuck displaces the workpiece chuck in a horizontal direction perpendicular to the tool axis and in a vertical direction to displace a workpiece between the station and a position aligned on the tool axis with the tool chuck.
A significant advantage of the milling and boring machine according to the invention is that both the tool chuck which can rotate about and move along one axis and the workpiece chuck which can move about multiple axes are mounted on the same monoblock-style upper housing part. This ensures excellent force transmission, extreme rigidity, and accurate alignment of the chucks with each other during the machining operation. The workpiece chuck connected via the cross slide to the upper housing part not only makes the perpendicular, that is horizontal and vertical, movements necessary for machining the workpiece, but also can take care of picking up an unmachined workpiece bringing it into position for machining, and then afterward taking the machined workpiece back to the supply station for dropping off. No separate workpiece feeding system or grab is needed; the same chuck that holds the workpiece during the machining operation is the only part that touches it except the tool that machines it. The result is a streamlined work flow and high productivity. The time between succeeding machining operations can be reduced to a bare minimum.
Another substantial advantage of this invention is that, since both the chucks that handle the workpieces and the tools are mounted on the upper housing part, hanging therefrom, the chips and particles generated by the machining operation will not foul them. Instead these chips will fall down to the lower part which can be provided underneath the tool chuck with a catch basin that efficiently collects them.
According to another feature of the invention the upper housing part has a vertical surface extending above the supply station. A horizontal guide on the vertical surface and extending perpendicular to the tool axis carries the cross slide. The cross slide includes a horizontally displaceable element movable along the horizontal guide and a vertically displaceable element movable vertically on the horizontally displaceable element and carrying the workpiece chuck. The workpiece chuck is pivotal about a vertical axis on the vertically displaceable element and is pivotal about a horizontal axis transverse to the tool axis on the vertically displaceable element. Thus five-sided machining of the workpieces is possible.
The supply station includes conveyor means for horizontally transporting workpieces into and out of the supply station. Typically the conveyor is one or more belt-type conveyors that bring a unmachined workpieces into reach of the workpiece chuck and that take out machined workpieces dropped off by the workpiece chuck. The infeed and outfeed belts are immediately adjacent each other so that the workpiece chuck has only a short distance to travel after dropping off a machined workpiece to pick up an unmachined one.
Furthermore according to the invention a magazine holding a plurality of tools on the lower housing part is provided beneath the tool chuck. An automatic tool changer is provided on the upper part for taking a tool from the magazine and inserting it in the tool chuck and for taking a tool from the tool chuck and inserting it in the magazine. Thus the same tool chuck can perform different operations. The tool changer is normally a two-jaw grab.